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Groups > linux.kernel > #1646388

Re: RFC: better timer interface

From Thomas Gleixner <tglx@linutronix.de>
Newsgroups linux.kernel
Subject Re: RFC: better timer interface
Date 2017-05-21 20:20 +0200
Message-ID <tJDCp-2Pf-13@gated-at.bofh.it> (permalink)
References <tHJ9f-56f-3@gated-at.bofh.it> <tHMTw-7r2-11@gated-at.bofh.it> <tHN3c-7uo-21@gated-at.bofh.it> <tHRgu-1Pj-13@gated-at.bofh.it> <tJCGl-2fH-1@gated-at.bofh.it>
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On Sun, 21 May 2017, Thomas Gleixner wrote:
> On Tue, 16 May 2017, Arnd Bergmann wrote:
> > On Tue, May 16, 2017 at 5:51 PM, Christoph Hellwig <hch@lst.de> wrote:
> > > Yes, that sounds useful to me as well.  As you said it's an independent
> > > but somewhat related change.  I can add it to my series, but I'll
> > > need a suggestions for a good and short name.  That already was the
> > > hardest part for the setup side :)
> > 
> > If we keep the unusual *_timer() naming (rather than timer_*() as hrtimer
> > has), we could use one of
> > 
> > a) start_timer(struct timer_list *timer, unsigned long ms);
> > b) restart_timer(struct timer_list *timer, unsigned long ms);
> > c) mod_timer_ms(struct timer_list *timer, unsigned long ms);
> >     mod_timer_sec(struct timer_list *timer, unsigned long sec);
> 
> Please make new functions prefixed with timer_ and get rid of that old
> interface completely. It's horrible.
>  
> timer_init()
> timer_start(timer, ms, abs)

I'm not even sure, whether we need absolute timer wheel timers at
all, because most use cases are relative to now.

But it's easy enough to provide them. All we need for that is something
like

	unsigned long time_msec;	

which gets incremented every tick by the appropriate amount of
milliseconds.

Having that would also allow to replace all the

       end = jiffies + msec_to_jiffies(xxx);

       while (time_before(jiffies, end))
       	     ....

constructs with a milliseconds based machinery. So we can remove all
*_to_jiffies() interfaces over time.

Thanks,

	tglx

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Thread

RFC: better timer interface Christoph Hellwig <hch@lst.de> - 2017-05-16 13:50 +0200
  [PATCH 3/9] kthread: remove unused macros Christoph Hellwig <hch@lst.de> - 2017-05-16 13:50 +0200
    Re: [PATCH 3/9] kthread: remove unused macros Petr Mladek <pmladek@suse.com> - 2017-05-17 14:20 +0200
      Re: [PATCH 3/9] kthread: remove unused macros Christoph Hellwig <hch@lst.de> - 2017-05-18 10:30 +0200
  [PATCH 8/9] tlclk: switch switchover_timer to a modern timer Christoph Hellwig <hch@lst.de> - 2017-05-16 13:50 +0200
  [PATCH 6/9] s390: switch topology_timer to a modern timer Christoph Hellwig <hch@lst.de> - 2017-05-16 13:50 +0200
  [PATCH 4/9] workqueue: switch to modern timers Christoph Hellwig <hch@lst.de> - 2017-05-16 13:50 +0200
  [PATCH 7/9] s390: switch lgr timer to a modern timer Christoph Hellwig <hch@lst.de> - 2017-05-16 13:50 +0200
  [PATCH 9/9] timers: remove old timer initialization macros Christoph Hellwig <hch@lst.de> - 2017-05-16 13:50 +0200
    Re: [PATCH 9/9] timers: remove old timer initialization macros Arnd Bergmann <arnd@arndb.de> - 2017-05-16 21:50 +0200
      Re: [PATCH 9/9] timers: remove old timer initialization macros Christoph Hellwig <hch@lst.de> - 2017-05-18 10:30 +0200
  [PATCH 2/9] timers: provide a "modern" variant of timers Christoph Hellwig <hch@lst.de> - 2017-05-16 14:00 +0200
    Re: [PATCH 2/9] timers: provide a "modern" variant of timers Randy Dunlap <rdunlap@infradead.org> - 2017-05-16 21:30 +0200
    Re: [PATCH 2/9] timers: provide a "modern" variant of timers Arnd Bergmann <arnd@arndb.de> - 2017-05-16 22:10 +0200
      Re: [PATCH 2/9] timers: provide a "modern" variant of timers Christoph Hellwig <hch@lst.de> - 2017-05-18 10:30 +0200
        Re: [PATCH 2/9] timers: provide a "modern" variant of timers Christoph Hellwig <hch@lst.de> - 2017-05-18 10:50 +0200
          Re: [PATCH 2/9] timers: provide a "modern" variant of timers Arnd Bergmann <arnd@arndb.de> - 2017-05-18 11:00 +0200
            Re: [PATCH 2/9] timers: provide a "modern" variant of timers Christoph Hellwig <hch@lst.de> - 2017-05-21 09:10 +0200
              Re: [PATCH 2/9] timers: provide a "modern" variant of timers Arnd Bergmann <arnd@arndb.de> - 2017-05-21 14:30 +0200
          Re: [PATCH 2/9] timers: provide a "modern" variant of timers Thomas Gleixner <tglx@linutronix.de> - 2017-05-21 20:00 +0200
            Re: [PATCH 2/9] timers: provide a "modern" variant of timers Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-21 20:30 +0200
    RE: [PATCH 2/9] timers: provide a "modern" variant of timers David Laight <David.Laight@ACULAB.COM> - 2017-05-19 12:50 +0200
      Re: [PATCH 2/9] timers: provide a "modern" variant of timers 'Christoph Hellwig' <hch@lst.de> - 2017-05-21 09:00 +0200
  [PATCH 5/9] powerpc/numa: switch topology_timer to modern timer Christoph Hellwig <hch@lst.de> - 2017-05-16 14:00 +0200
  Re: RFC: better timer interface Arnd Bergmann <arnd@arndb.de> - 2017-05-16 17:50 +0200
    Re: RFC: better timer interface Christoph Hellwig <hch@lst.de> - 2017-05-16 18:00 +0200
      Re: RFC: better timer interface Arnd Bergmann <arnd@arndb.de> - 2017-05-16 22:30 +0200
        Re: RFC: better timer interface Christoph Hellwig <hch@lst.de> - 2017-05-18 10:30 +0200
        Re: RFC: better timer interface Thomas Gleixner <tglx@linutronix.de> - 2017-05-21 19:20 +0200
          Re: RFC: better timer interface Thomas Gleixner <tglx@linutronix.de> - 2017-05-21 20:20 +0200
            Re: RFC: better timer interface Arnd Bergmann <arnd@arndb.de> - 2017-05-22 13:30 +0200
              Re: RFC: better timer interface Thomas Gleixner <tglx@linutronix.de> - 2017-05-22 21:30 +0200
            RE: RFC: better timer interface David Laight <David.Laight@ACULAB.COM> - 2017-05-23 13:40 +0200
              RE: RFC: better timer interface Thomas Gleixner <tglx@linutronix.de> - 2017-05-23 14:00 +0200
                RE: RFC: better timer interface David Laight <David.Laight@ACULAB.COM> - 2017-05-23 15:00 +0200
                RE: RFC: better timer interface Thomas Gleixner <tglx@linutronix.de> - 2017-05-23 15:10 +0200
          Re: RFC: better timer interface Arnd Bergmann <arnd@arndb.de> - 2017-05-22 15:40 +0200
            Re: RFC: better timer interface Thomas Gleixner <tglx@linutronix.de> - 2017-05-22 21:20 +0200

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